US3507695A - Utilization of sound wave energy - Google Patents

Description

April 21, 1970 H. T. SAWYER UTILIZATION OF SOUND WAVE ENERGY Filed April 18, 1967 INVENTOR.

flrmeJss s 54w SQMMY mm QM United States Patent 3,507,695 UTILIZATION OF SOUND WAVE ENERGY Harold T. Sawyer, Los Angeles, Calif., assignor of seventeen and one-half percent to Vernon D. Beehler, Los Augeles, Calif.

Continuation-impart of application Ser. No. 480,310, Aug. 17, 1965. This application Apr. 18, 1967, Ser. No. 631,736 The portion of the term of the patent subsequent to Mar. 21, 1984, has been disclaimed Int. Cl. B08b 7/02 US. Cl. 134-1 Claims ABSTRACT OF THE DISCLOSURE Method for generating sound wave energy and utilizing it in such fashion that an appropriate tool is resonated in such fashion as to be capable of sending out sound wave energy of desired frequency and amplitude to do work. A typical apparatus by means of which the method can be practiced encompasses a light weight hollow essentially spheroidal shell of stiff resilient consistency which together with certain structural members and a source of power comprises a sonic energy source. The motor is specifically mounted so that the body of the motor itself revolves in conical fashion about an eccentric bearing support at one end and is held in a fixed radial and longitudinal position by means of a resilient concentric pivot bearing support at the other end. Only one connection is made between the spheroidal body-and one of the bearing supports for the revolving motor. As a result the sinusoidal force thusly created by the product of the mass of the motor and its velocity around its eccentric bearing is transported to the spheroidal body at only one point. When the motor is properly selected with respect to its speed of rotation and eccentricity of mounting together with proper design of the structure, a sinusoidal force is created which when transferred to the shell body of specific design brings the body into resonance at a selected frequency and emits sound wave energy. The sound wave energy thus created can be made to do work either by passing it through a liquid or by connecting the spheroidal body directly to a tool for retransmission of sound energy.

This is a continuation-in-part of copending application Ser. No. 480,310 filed Aug. 17, 1965, now Patent No. 3,357,033.

By way of example the method can be operated as a low power sonic energy source for generating and transmitting omnidirectional sound waves of high energy amplitude and intensity in the lower sonic frequency range when submerged below the surface of liquids of virtually any kind or nature. When used in this fashion, a wand can be used to wash fabrics, mix together different liquids, stir liquids such as paint, disperse pigments or dye in a liquid, or operate a surface conditioning or a cleaning tool such as the sponge applicator in a holder shown in applicants copending application Ser. No. 483,463, filed Aug. 30, 1965, now US. Patent No. 3,402,009. The method may also be made use of for therapeutic treatment where deep therapy treatment is required in baths or physical contact at any desired degree of intensity.

It is therefore among the objects of the invention to provide a new and improved method for utilizing sound wave energy to do work.

Another object of the invention is to provide a new and improved method of utilizing sound wave energy in such fashion that it is possible to embody the method in low power hand operated portable devices which may either be immersed in liquid in a container such as basins, tubs,

Ice

cans, and the like or which may be made use of in connection with appropriate resonant carrying media such as a sponge or urethane material capable of transmitting the employment of the method to some surface upon which work is to be performed.

With these and other objects in view, the invention consists in the construction, arrangement, and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings. To illustrate how the method of utilizing sound wave energy can be made use of reference is made by way of example to what may aptly be described as a sonar wand illustrated in the accompanying sketches.

In these drawings:

FIGURE 1 is a longitudinal sectional view of a typical device;

FIGURE 2 is a cross-sectional view taken on the line 22 of FIGURE 1;

FIGURE 3 is a cross-sectional view taken on the line 3-3 of FIGURE 1;

FIGURE 4 is a fragmentary sectional view showing the eccentric mounting on the outside end of the rotational driving force motor;

FIGURE 5 is a cross-sectional view taken on the line 5-5 of FIGURE 1; and

FIGURE 6 is a schematic drawing of a controlling rheostat.

In order to more thoroughly understand the method of utilizing sound energy herein disclosed, and for describing in detail the device of the drawings it should be understood that sonic energy as used herein for cleaning is not to be confused with high frequency sound waves and which may have a lower limit at 20,000 cycles per second or slightly higher.

' It has been demonstrated that ultrasonic energy in the form of ultrasonic sound waves are useful in cleaning the surfaces of solid objects of grease or other contamination which may have been deposited on such surfaces in the form of a thin film even as small as a structure of molecules. The desired working range of frequencies for surface cleaning has been established to be within a range approximating 23,000 to 40,000 cycles per second. The cleaning action on the surface contamination film has been described as one causing rapid formation and violent collapse of minute microscopic bubbles within the cleaning solvent of the liquid combined with an effect known as impolsion. Implosion is an effect created by the combination of inherent reflection and cavitation associated with ultrasonic waves. The reflection energy thus created at the surface and with little penetration effect into the solid material, is aided by minute cavitation bubbles of the solvent, which causes an implosion that pulls or rips off the molecules of the contamination surface film from the solid surfaces.

This manner of cleaning has been demonstrated to be restricted to the use of ultrasonic energy for several reasons. Ultrasonic waves for example, are minutely shorter in wavelength than are those in the lower sonic range, and their tendency to efficiently reflect their wave energy from solid surfaces is analogous to microwaves and are therefore an important element in ultrasonic energy surface cleaning. Since ultrasonic wavelengths are shorter as compared to sonic energy wave lengths, they correspondingly produce substantially less and small penetration of solids and less cavitation within the liquid medium than sonic energy at the same energy levels.

Also, ultrasonic energy sound waves are usually associated with small amplitudes and the resultant cavitation within the liquid is thusly small but desirable for ultrasonic cleaning.

It has also been established that ultrasonic energy may be generated to produce high energy amplitudes but only at extremely high and inefficient powers which has been demonstrated to produce undesirable effects such as damage to the material to be cleaned in the form of chipped surfaces and requirements leading to a high degree of ultrasonic frequency shielding to comply with the Federal Communications Regulations.

It has also been demonstrated that when ultrasonic energy sound waves are generated for surface cleaning even slightly below 20,000 cycles per second as designated by the higher limit of the audible or sonic wave energy range, an effect is produced whereby a penetrable high pitch and audible sound is produced which is unhealthy to the human body and many times causing broken ear drums and thusly requiring the use of ear plugs. Therefore, ultrasonic energy cleaning equipment has been designated to operate safetly above the lower ultransonic energy value of 20,000 cycles per second, and the practical lower limit operating value has been established commercially to be at 23,000 cycles per second.

In addition, practically all devices heretofore constructed for ultrasonic surface cleaning have been relatively massive, permanent and stationary in character necessitating many precautions.

Ultrasonic sound waves by nature are higly directional and their application to ultrasonic cleaning requires a number of energy sources per fluid tank to insure radiation coverage of the solid materials to be surface cleaned. Also by nature, ultrasonic energy waves are easily absorbed by the liquid medium and solid materials to be cleaned. The efficiency of such devices is considered to be extremely low. Because of this and other factors, very high powers are generally required and typically one kilowatt is required for cleaning tanks, from 13 to 15 gallons capacity, and in each case the power supplies are remotely located and are carefully shielded to comply with FCC regulations. There are no known harmfull effects to the human body by ultrasonic radiation other than the danger of the sound effects to the ear.

.It is recognized that vibrators have been in use for a considerable length of time and are used for various sundry purposes such for example, mechanical shakers for bins, mechanical shakers for conveyors, agitators for expelling air and water from cement during placement of concrete, hand vibrators for massage treatment, agitation of material such as grain being transported from one place to another through conduits, compaction of molding materials in mold form, impulse and gyration devices used in washing machines and impulse machine mechanisms, etc. It is of interest to note in these cases that a relatively small powered vibratory mass is utilized to impact and physically disturb large masses at periodic cycles generally considered to be at 60 cycles or lower. The effect produced in the relatively heavy large masses is one of shaking, vibratory, impulse, pulsation, gyration, movement, displacement, pushing, etc.

The differences in the generation and transmission of energy as exemplified by the two latter examples are at considerable variance with each other and are limited to their own usefulness by the manner in which their energy is produced and transmitted. Likewiise, it is also known that the use of under liquid sonic energy sound waves in the lower sonic range for useful applications relative to this invention are by their physical nature also pertinent to the successful use of this invention.

Unlike ultrasonic energy cleaning equipment which requires relatively high power high frequency waves at extremely low amplitude and minute cavitation, the sonar wand device essential requirements dictate a small hand operated sonic energy source of extraordinary high eificiency and low power and of particular importance to the invention the requirements have been demonstrated to dictate the use of sound Wave energy in the low sonic range for production of large wave energy amplitudes at high intensity for the production of underwater energy having the necessary degree of penetration and cavitation for its useful application.

Sonic sound waves in the lower sonic range have longer wavelengths than ultrasonic energy waves and therefore by nature are conducive of a much higher degree of penetration of the submerged materials within a liquid; and they are also more conducive by nature to the production of high energy amplitudes at low powers. The continuous reversals of these high amplitude energy waves produce an exceptionally high degree of penetration and cavitation within the liquid and the submerged materials. The continuous reversal of the high amplitude energy at the desired frequency within the liquid and submerged materials, causes the alternate production and collapse of millions of bubbles within the liquid and submerged materials thus creating an implosion effect which rips away the .dirt and contamination from the submerged materials.

The implosion bubbles increase in size with a reduction of requency and are therefore a function of wavelength. For example, at 20,000 cycles per second the bubble size is 40 microns, and at 10,000 cycles per second the bubble size is microns and barely visible. In the lower sonic range at 150 cycles the implosion bubble size is approximately 158 microns and clearly visible. :It is therefore evident that the implosion effect and resulting cavitation within the liquid and submerged materials is of higher intensity at frequencies in the lower sonic range.

It is also known that high frequency or ultransonic energy waves are highly reflexive and by nature do not have the ability to penetrate submerged materials deeply and which thusly has been demonstrated by ultrasonic cleaning equipment, microwaves and underwater acoustic range finding equipment. The degree of peneration is therefore a function of wave length.

Since underwater sound waves travel at a speed of 4,800 feet per second, the wavelength of ultrasonic energy waves of 24,000 cycles per second is 0.2 feet as compared to a wavelength of 40 feet for sonic waves of cycles. By

comparison therefore, sonic energy waves in the low frequency range have by comparison therefore a far greater penetration effect than those referred to by comparison.

In accordance with the invention the method can be practiced by making use of a low power sonar wand device which utilizes a small rugged lower power sonic energy source typically between 45 and 70 watts which is reliable, self-contained, sound wave and electrically sealed and isolated from the handle or supporting means. The rotating mass driving force body consists typically of a standard gearless shaded pole, synchronous or series motor approximately 1% pounds, or may be any rotating mass which may be powered by air, Water or by other means and which may be suspended and substantially sound wave isolated at one end, and directly coupled at the other end through an appropriate eccentric shaft and bearing to a singular pedestal mechanism to its counterpart and supporting structure which consists of a thin wall substantially spherical radiator shell whose nonrigid cavity supports and encompasses the entire sonic energy producing mechanism.

Thev radiator shell supporting structure, approximately 4 inches in diameter, has an infinitely small mass as compared to the rotating mass within its cavity since its shell thickness approximates or inch in thickness. Representative radiator shells weigh 1% to 2 /2 ounces. Because of the small mass of thesupporting radiator shell body as compared to the infinitely large mass of the contained driving force assembly body within the cavity, there is but a small velocity reduction between the large rota tional body and the supporting body.

Because of these factors, the driving force mass assembly moves with a large energy velocity that produces an extraordinarily efficient energy output which is capable of generating and transmitting sound waves in the desired lower sonic range typically from 50 to 150 cycles per second at exceptional high energy amplitudes. Since the radiator shell mass is small relative to the rotational driving force mass, the sound waves radiated from the outer surface of the radiator shell are of exceptionally high intensity when the radiator shell is liquid loaded. The combination of these factors when produced in their proper parametric relationship produces a highly efficient sonar source of energy as compared to the other known sonar devices which results in an exceptional production of cavitation and penetration of the materials within the contained aqueous medium, and which in turn is an important element of the invention.

A prerequisite to a good understanding of the present invention involves a full understanding of the sonic energy producing source which consists of a rotating body driving force which is mounted within its supporting radiator shell, and in the aspect of meeting the problems such as physical size, weight, wave amplitude, desired frequency, omni-directional radiation, efficiency, desired wave energy intensity and stable frequency transmission.

The driving force which causes the radiator shell to oscillate at any desired frequency typically at a value between 50 to 150 cycles per second is provided by the bearing at one end of the motor to which is attached a rotating eccentric. The fact that the rotational axis does not coincide with the center of mass of the eccentric provides a force much in the same manner that an unbalanced automobile wheel produces whose frequency is proportional to the velocity. The structure of the radiator shell is being flectured in cyclical manner at a rate commensurate with the speed of the rotational mass in revolutions per second as caused by the eccentric offset of the symmetry axis of the rotor with respect to the end bearing and as transmitted thereon by the driving force pedestal to the cavity shell. The alternating sinusoidal sound waves of compression and tension are launched by the surface of the radiator shell which is acoustically coupled to the liquid.

There is a parametric relationship between the rotational velocity and the rotationed mass and offset of the eccentric and the sonic energy drive force transmitted into the aqueous medium which has been examined experimentally, and over a limited range, from 50 to 150 cycles per second, the amount of sonic energy transmitted into the liquid medium is proportioned to the angular velocity of the rotor mass and the product of the mass of the eccentric and the displacement of its center of mass from the rotational axis.

The problems of efficiency and weight are related chiefly to the sonic energy source configuration. In order to obtain an extraordinary degree of efficiency and wave energy amplitude a self powered gearless rotating mass of sufficient weight and desired rotational velocity was chosen since the driving force thus generated is directly related thereto. In order to take full advantage of this driving force relationship in terms of the essential requirements set forth, the rotating mass was located within the spherical thin radiator shell in such a fashion that the resultant force is coupled to the radiator shell by a single pedestal base and in such a position that its radius of gyration was located at the center of the spherical radiator shell.

The other main direction was to refine the sup-port means for the rotating mass, in order that the full effect of the rotational driving force velocity mass be coupled to the radiator shell at a single location. This was accomplished by supporting and anchoring one end of the rotating mass by means of a resilient mount having the necessary longitudinal rigidity and radial flexibility to support the rotating mass. The outer end of the resilient mount is supported and isolated from the cavity shell,

thus permitting a free transmission of cyclical driving force energy to flecture the supporting radiator shell at a single location.

Although other means of suspension are possible, the spring method was chosen because it is also an excellent economical means of reducing and substantially isolating any energy loss which might otherwise reach the handle supporting structure, and to also permit the total rotating mass structure to be turned and translated in any direction without causing torques that disturb the angular orientation of the rotor axis relative to the supporting structure. Also and of equal importance the driving force pedestal coupling to the radiator shell is located within the cav ty and at a single point which is directly below the horizontal axis of the driving force and vertically below the center of the radius of gyration of the rotating mass.

The particular location was chosen in order to obtain a maximum of fiecturing energy being coupled to the shell, and to eliminate any gyration effect which might cause a loss of effective radiator shell energy transmission and produce an uncomfortable effect to one who would hold the sonar wand.

It is also of equal importance that the encompassing rounded radiator shell be vastly smaller nonrigid mass and of thin wall stiff material such as Fiberglas, for exexainple, which has exceptional strength, flexural and insulating qualities. Since the spherical shell cavity is nonrigid and is perturbed cyclically at only one location, it is by design and demonstrated to be capable of being fiectured sinusoidally with maximized cyclic velocity amplitude and in a manner inherently conducive to transmitting a fundamental frequency commensurate and in synchronism to the fundamental frequency as developed by the velocity of the rotating mass.

It should be pointed out that other known sonic energy devices are rigid in character with supporting means for the driving force at several positions within a radiator shell which in turn limits the flexture capacity of the radiator shell and generates sound waves at more than one location within the radiator shell which is highly conducive to wave interference thus leading to a substantial loss of transmitted energy and efficiency.

It is therefore an important element of this invention as substantiated in the prior two paragraphs that the design of the sonic energy source is extremely simple and inherently eflicient. The simplicity involves the full utilization of the integral mass driving force to produce unusually high amplitudes of wave energy at low power thus utilizing to advantage a minimum of weight. It is efficient because rotating mass is vastly greater than the supporting radiator shell, and the suspension means is removed and isolated from the cavity shell thusly transmitting effectively all of the driving force energy to the radiator shell which is nonrigid and perturbed at only a single location thus permitting radiation of a single and fundamental wave pattern without interference from other sources, and also that it is free of gyration effects which would inherently reduce the effective transmission of useful sound wave energy.

Moreover when the driving force is understood to be force resulting from the calculation F (force)=E (degree of eccentricity) XM (mass) r.p.m.

the most economical way to increase the force is to increase the mass thereby to make the ratio high between the mass at the source of power and the diaphragm which expends the work energy. Special circumstances however may be served by increasing other factors in the force equation when, for example, the diaphragm is mounted on a tool of appreciable weight.

An important feature of my invention in terms of efficiency is that the sonic energy source operates at a stable frequency through its effective operating range. The inherent design previously described in the foregoing paragraphs lends itself particularly to a stabilized frequency source since a large internal rotating mass is driving what may be construed as an infinitely smaller supporting structure radiator shell mass of thin wall construction which has its own resonant frequency infinitely higher than that of the rotating force frequency. It is also an important feature of this invention that such frequency stability adds to the controllability of the sonic energy source by remote means.

The problem of omni-directional sound waves from the sonic energy source is an essential element of this invention in order to fully meet the requirements for the useful applications heretofore described. It has been demonstrated that a nonright thin spherical shell radiator cavity when flexturcd, internally and cyclically as heretofore described, emits sinusoidal sound waves in spherical fashion from the outer shell surface which is in direct contact with a liquid. The radiator shell encompasses and is an integral part of the sonic energy source. The sonic energy source of this invention is somewhat analogous to a conventional radio loud speaker wherein the oscillator driving force coil having relatively large mass is mounted on a rigid frame, the parameter of which encompasses a very thin wall transmitter diaphragm.

The armature of the driving force frequency generated coil is fastened by a single pedestal to the center of the diaphragm shell and in such a manner that the diaphragm shell of smaller mass is perturbed and fiextured in synchronism with the oscillator coil, and thusly transmitting sonic sound waves which are directional only as related to the shape of the diaphragm and audible in air.

The present invention likewise develops sound wave energy and in sinusoidal fashion, however, the total driving force mass is mounted within a spherical radiator shell in order to produce a maximum intensity of sound wave amplitude and to radiate omnidirectional sound wave energy.

The selection of a spherical radiator shell also was conducive to the solution of other problems which are necessary elements of this invention such as physical size, weight. Since a spherical object has a maximum surface area relative to its physical volume, it therefore provides a configuration for low power operation whereby a maximum cavity sheet volume may be utilized for encompassing the driving force physical mass while having the advantage of utilizing the maximum surface area to in turn transmit the sonic energy Waves of high intensity.

Since the spherical cavity shell in terms of efficiency must be free of internal structural members, the spherical shape by nature is known to be strong and freely flextured with a minimum of surface stress since the entire surface is free to move when being perturbed in a cyclic manner. It has also been demonstrated that the sonar wand device having a spherical shell approximately 4 inches in diameter would provide sufficient buoyancy to float the device in a nearly submerged condition when in liquid and to be substantially weightless when used by the hand.

Also, another important element of this invention is to eliminate gyration or low frequency vibratory conditions within the desired operating frequency range and which might be present should an improper sonic source be contemplated. It has been demonstrated that a spherical shell is ideally adaptive to this solution since the center of the radius of gyration of the rotating mass driving force mechanism may be accurately located at the center of the supporting spherical cavity, and under such conditions gyration effects are only noted at a near stall condition of the rotating mass. And under operation the dynamic balanced system tends to produce a gyro effect which is desirable and indicative of an inherently stable system.

Another essential element of this invention concerns safety. It has been demonstrated that a radiator shell material such as by example reinforced Fiberglas, has many of the best physical properties for construction of the cavity shell. It is also known to be one of the best materials known for insulation properties and having one of the highest values of dielectric means, the entire Wand would be fabricated of similar material and the total device would in itself be an excellent insulator. In addition the sonar source portion of the device is independently constructed, insulated and sealed. Similarly the handle of the wand is constructed for safety.

Another important element of the invention concerns the object of isolating the passage of sound wave energy from the handle of the wand, the requirements being to isolate and conserve the sound wave energy to the radiator shell structure of the sonar source in order to provide maximum efi iciency and to also isolate and eliminate any undesirable transfer of energy to a human who might hold the sonar wand in his hand. The solution was accomplished by sealing the handle to the sonic energy source with a material which has both the property of excellent sealing strength, high dielectric strength and the additional desired property of isolating and absorption of sound wave energy in the frequency operating range of this device.

As an additional precaution against further sound wave leakage, the handle stock material at the point of isolation was provided with a sharp tapered edge to limit the passage of sound wave energy.

As a further precaution, the multitude of compressed wafers of similar sound Wave material are sealed at unequal distances from each other in order to block any further sound wave leakage to the handle. The wafers in addition to having inherent sound wave absorption properties are unequally spaced in order to break up and cancel sound wavelength pattern which might exist.

It has been demonstrated that the solution as outlined has effectively cancelled the penetration of sound waves to the handle when the sonic source is liquid loaded, and only a minor leakage is noticeable when operating in air.

The difficult problem has been accomplishment of providing a low power, light weight, hand operated and sound wave isolated source of sonic energy sound waves having extraordinary efficiency, and which radiates omnidirectional sound waves in spherical fashion, high amplitude and intensity and with excellent frequency stability from a thin shell non-rigid liquid loaded sound radiator having an unusually small surface area, which receives its driving force from a simple inexpensive but relatively large integral driving force mass.

In the embodiment herein disclosed for illustrative purposes there is shown a sonic energy source radiator shell indicated generally by reference character 10 consisting of two parts namely, what may aptly be described as a base section 11 and a cover section 12. The shell is typically spherical, the parting line 13 lying in an oblique direction as shown in FIGURES 1 and '2 wherein an annular ring 14 which may be separate or an integral part of either the base section 11 or the cover section 12 forms a means of attaching the sections together in sealed relationship. An example of an effective material having excellent dielectric strength for the radiator shell 10 has been found to be reinforced glass fiber. It is important that the material be strong and stiff and of exceptional flectural and dielectric strength so that the thickness or gauge of the shell can be kept to a relative minimum for purposes that are pertinent to efficient transmission of energy and to provide a minimum mass.

In the base section there is provided a cavity shell pedestal base 15 which is preferably cast or molded contemporaneously with the molding or casting of the base section as a whole. It is significant that the pedestal be located midway between opposite right and left hand ends of the spherical cavity portion 62 of the shell as viewed in FIGURE 1.

It is also significant relative to FIGURE 1 that the vertical centerline position of the cavity shell pedestal base is also vertically in line and directly below location 61 which is also the center of the radius of gyration of the rotational mass 30 which may be typically a motor as shown.

A driving force pedestal 16 has a pedestal mounting base 17 anchored to the cavity shell pedestal base 15 by means of epoxy and screws 18. A reinforcing flange 19 extends throughout the length of the pedestal. As shown the pedestal is arcuate and has substantially the same radius of curvature as the inside of the radiator shell cavity 62 in order to permit the driving force pedestal to hug the cavity shell as much as possible thereby to preserve a maximum amount of space within the cavity for other equipment. At the end of the driving force pedestal 16 remote from the base mounting 17 is a bearing housing 21 in which is located a roller hearing assembly 22 in which is a cylindrical bore 23. A crank 24 has a stub shaft 25 freely inserted in the cylindrical bearing 22 at the centerline. It is significant that the exterior of the stub shaft have the proper symmetrical curvature for insertion within roller cylindrical bearing 22 so that the stub shaft 25 will be freely aligned and supported at any angle within the range of the angular rotational relationship provided for in the device. In the crank 24 is a bore 26 eccentric with respect to the center line of the stub shaft 25, the bore 26 providing a means by which a motor shaft 28 can be secured to the crank 24. Mounted in this fashion the rotational axis of the rotating driving force mass or motor 30 does not coincide with the center line of the cylindrical bore of the supporting roller bearing 22. For a relatively small device having a radiator shell of about 4 inches in diameter the eccentricity can be between about to inch.

At the end of the housing of the motor 30 opposite from the bearing housing 21 the motor shaft terminates within its own supporting motor bearing and a motor supporting suspension means in the form of a coiled resilient spring 32 is secured internally to the motor housing casing 31.

Molded with and forming part of the base section 11 is a yoke 35. In the yoke is a bore 36, having a tapered outer end, and a cylindrical inner end. A cylindrical portion 38 lying within the supporting suspension spring 32 has a flange 39 underlying the innermost coil of the spring. A key 40 positioned in a keyway 41 is forced against the mounting spring 32 in order to anchor it in a position within the bore 36 by means of a set screw 42. A sealant plug 43 is used to seal the set screw mounting once the spring is properly positioned.

In the yoke at the end opposite from that occupied by the spring is a passage 44. At about the area of the passage the yoke has a portion 45 of reduced diameter. A tubular handle 46 of material such as Fiberglas has an inside wall 47 substantially larger in diameter than the outside diameter of the portion 45 leaving a space therebetween which is filled with a sealant 47 which has excellent sonic sound wave isolation and absorbing properties for the proposed operating frequencies in the lower sonic range. The sealant material having high temperature and dielectrc strength properties, is employed to isolate the tubular handle 46 from the yoke 35 and this accomplished additionally by a separating shoulder and sealant filled spacing 48 of the yoke 35 from a feathered edge 49 of the handle 46. In order to prevent and absorb any further leakage of sound waves beyond this point and outwardly through the handle, there are provided low frequency sound Wave absorbent wafers 50, 51 and 52 which are compressed and sealed at staggered intervals through the interior of the handle. The wafers are placed at predetermined distances apart with care being taken that the distance between any two wafers is different fromthe distance between every other pair of wafers, regardless of how many wafers may be used and that the distances are not even multiples or fractions of the maximum distance.

10 A cap 54 of material such as Fiberglas seals the outermost end of the handle.

Electric leads 55 and 56 extend from a terminal base which is mounted centrally in the motor housing 31 and at a position near to but slightly remote from the secured position of the supporting suspension spring 32. The leads thusly are extended from the terminal base and pass centrally and outwardly through the motor housing 31 and spring 32, and thence outwardly a yoke section 35 which has two small bores for passage of each wire and which is sealed with insulating material. The wires are thence extended and continued outwardly through passage 44 and in which passage the wires are encapsulated and sealed with a potting compound 44 containing excellent properties of exceptional dielectric strength and sound wave isolation. Continuing and outwardly from passage 44 the wires pass through two bores in a seal plug 45' of material such as Fiberglas and in turn the wire passages are sealed with insulating material and the seal plug 45' is seated within the yoke portion 45 thus closing the passage 44. The wires then continue outwardly through the insulation supporting wafers 50, 51 and 52 and to the exterior for suitable connection to a source of power.

On occasions there may be some need to vary the speed of the rotating mass or typically the speed of motor 30 whose speed may be controlled by employing a rheostat 60 with power supplied by some external wires 55 and 56. By varying the speed of rotation of the motor, the frequency of the sonic energy sound waves are thus varied and in synchronism, which may be desirable when sonic energy sound waves are made use of for medical therapy.

In operation the rotational driving force mass 30 may be typically a low power gearless series or shaded pole motor 30 having a power rating in a range between 40 and watts and which may be operated with AC synchronous or DC power and at a speed range which may be selected between 3000 and 9000 rpm. One end of the motor mass has a resilient mounting supporting means which is in the form of the cylindrical coiled spring 32 which has the proper combined support and fiexural characteristics to permit a freedom of motion between the rotational motor mass and the resultant motion produced by the offset of the eccentric 24 with respect to its supporting bearing 22.

It is also significant relative to FIGURE 1 that the location of the radius of gyration 61 of the rotational mass of the motor 30 is located at a point which is at the center of the volumetric space encompassed and within the spherical shell chamber or cavity 62, and which also is in line with the sectional line 22.

Although a substantially spherical form of shell has been stressed as being the most ideally efficient, departure may be made from the spherical shape, wherein roundness may be confined, for example, to only one plane. Shells of such varied shapes may be employed as effective sound sources when the rotationally gyrating energizer is secured to the shell at a single point.

'When the shell is as shown it may be immersed in liquid and in that way impart sonic energy to the liquid. Where this is not desirable liquid may be brought into contact with the shell by means of some container such as a sponge, a stream or a resonant container and the liquid then, in a resonating condition, applied to the work. Tools of other types, not dependent upon liquid may also be mounted on the shell at the location where the gyrating element is connected to the shell and there balanced and tuned to the system, so as to perform work.

Further still, although there may be a substantial range of amplitude or eccentric throw within which the sound waves generated are effective, the more useful range in a hand portable device for effective operation at a moderate consumption of power is between about and inch for a shell of approximately 4 inches in diameter wherein a motor operating on 40 to 70 watts is made use of.

In the chosen embodiment the cyclical mass driving force has been described as an eccentrically mounted motor mass. Other means, however, may be productive of such a driving force, as for example, a weight on one side only of the axis of rotation or an unbalanced armature in the motor.

While the invention has herein been shown and described in what is conceived to be a practical and advantageous embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

Having described the invention, what is claimed as new in support of Letters Patent is:

1. A method for applying sound energy to a subject for performing work thereon comprising rotating a mass eccentrically about an axis of rotation at a rate sufficient to set up a sinusoidal driving force for creating a source of sonic energy, extending a portable diaphragm of still resilient consistency around said mass and spacing said diaphragm on all sides from said mass, transferring energy from said mass along a stiff rigid path to a single location on said diaphragm, holding said diaphragm at all portions thereof except at said single location in a condition clear of said subject, transferring said sonic energy from said source to said diaphragm, placing a tool in communication with said source and limiting the placement of said tool to a single location on said diaphragm, balancing the vibration capability of said tool with said sinusoidal driving force, and passing said sonic energy from said diaphragm to said subject through said tool.

2. A method according to claim 1 wherein the mass which is eccentrically rotating is relatively great and the mass of the diaphragm is extremely small by comparison.

3. A method according to claim 1 including encompassing the mass on all sides with said diaphragm which is substantially round throughout the extent of said diaphragm.

4. A method according to claim 1 including using an abrasive pad as said tool.

5. A method according to claim 1 including using a resilient medium as said tool and confining said resilient medium to a limited area.

6. A method according to claim 1 including transferring the energy from the mass at one end of the axis and supporting the other end of the axis and said diaphragm at the same location and spacing said last location peripherally from said single location.

7. A method according to claim 1 including using as said tool a medium containing liquid.

8. A method according to claim 7 wherein said liquid is a detergent.

9. A method according to claim 7 including using a sponge as said tool.

10. A method according to claim 7 including passing said liquid to a subject on which work is to be performed in a series of relatively small streams spaced laterally from one another, and passing the sonic energy through said streams.

References Cited UNITED STATES PATENTS 3,089,790 5/1963 Balamuth et al 134-1 3,139,101 6/1964 Wyczalek et al 134-186 3,166,772 1/1965 Bodine 1522 3,166,773 l/1965 Wyczalek 15-97 3,310,129 3/1967 Sawyer 18l.5 3,357,033 12/1967 Sawyer 1598 MORRIS O. WOLK, Primary Examiner J. T. ZATARGA, Assistant Examiner US. Cl. X.R. 1346, 17

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